Inhibitory effect of C-type natriuretic peptide on spontaneous contraction in gastric antral circular smooth muscle of rat  

C型钠尿肽抑制大鼠胃窦环行肌自发性收缩活动(英文)

作　　者：郭慧淑[1] 崔勋[1] 崔永根[2] 金成柱[3] 曹景宇[3] 李在琉[1] 许文燮[2] 

机构地区：[1]延边大学医学院消化生理学研究室 [2]延边大学医学院附属医院中心实验室 [3]全北大学医学院

出　　处：《Acta Pharmacologica Sinica》2003年第10期1021-1026,1062,共7页中国药理学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China, № 30160028.

摘　　要：AIM: To investigate the effect of natriuretic peptides on gastric motility and its possible mechanism. METHODS: Spontaneous contraction of gastric antral circular muscle of rats was recorded by four channel physiograph. The concentration of cyclic guanosine monophosphate(cGMP) was measured by radioimmunoassay. The distribution of natriuretic peptide receptors(NPR) was analyzed by autoradiograph. RESULTS: NPR existed in different regions of rat stomach and its density was the largest in gastric antrum. Atrial natriuretic peptide(ANP), brain natriuretic peptide(BNP), and C-type natriuretic peptide(CNP) all inhibited the spontaneous contraction of gastric antral circular smooth muscle. Among them, the inhibitory effect of CNP on the spontaneous contraction was the most potent and exhibited a dose-dependent manner. CNP-induced inhibition was diminished by LY83583(a kind of inhibitor of guanylate cyclase) and potentiated by zaprinist(a kind of inhibitor of cGMP sensitive phosphoesterase). CNP markedly enhanced the concentration of cGMP in antral smooth muscle. The inhibitory effect of CNP on spontaneous contraction was also inhibited by tetraethylammonium(a nonselective potassium channel blocker, TEA). CONCLUSION: The distribution density of NPR is the most in gastric antrum. CNP significantly inhibits gastric motility in rat gastric antrum. The inhibitory effect occurs via a cGMP dependent pathway and potassium channel is also involved in the relaxation induced by CNP in gastric antrial circular smooth muscle of rat.目的:研究钠尿肽对胃动力的作用及其可能的机制。方法:用四道记录仪记录胃窦环行肌条的自发性收缩活动;利用放射免疫技术测定cGMP的产生量;利用放射自显影技术分析钠尿肽受体在胃内的分布情况。结果:钠尿肽受体在大鼠胃的不同部位均有分布,但在胃窦部最多,ANP、BNP和CNP均能抑制胃窦环行肌条的自发性收缩,其中,CNP的作用尤为明显并呈剂量依赖关系,CNP的这种抑制性作用被鸟苷酸环化酶抑制剂LY83583所削弱,而用cGMP敏感的磷酸酯酶抑制剂zaparinist预处理时CNP的抑制作用明显增加,CNP明显提高胃窦环行肌cGMP的浓度,用非选择性钾通道阻断剂TEA预处理后发现CNP对胃窦环行肌自发性收缩活动的抑制作用明显减弱。结论:钠尿肽受体在大鼠的胃窦分布最多,CNP明显抑制大鼠胃窦环行肌的自发性收缩活动,CNP对大鼠胃窦环行肌自发性收缩活动的抑制效应是通过cGMP途径实现的,钾通道也参与CNP对大鼠胃窦平滑肌的舒张过程。

关 键 词：C-type natriuretic peptide pyloric antrum gastrointestinal motility cyclic GMP 

分 类 号：R33[医药卫生—人体生理学]